I believe he used the iron sights. That was his only choice as regardless of shims at all, Oswald would have known that disassembling a rifle, placing it in a paper bag, and then assembling it inside the TSBD would mean the scope could not be trusted as it had not been zeroed in in its assembled state which is the only way to zero in a rifle.
But the scope as the FBI found it needed to have shims. Did Oswald have shims prior to the assassination or is it possible that Ruth Paine damaged the rifle scope in her car and therefore while the rifle initially might not have needed shims, after Ruth Paines car journey the rifle would now require shims.
I believe he used the iron sights. That was his only choice as regardless of shims at all, Oswald would have known that disassembling a rifle, placing it in a paper bag, and then assembling it inside the TSBD would mean the scope could not be trusted as it had not been zeroed in in its assembled state which is the only way to zero in a rifle.
If I understand your "reasoning"..... You believe the WR, and that Lee Oswald was the assassin. And you further believe that he knew that the scope was worthless as an aid to firing the rifle accurately..... But he kept that worthless piece of junk attached to the rifle even though it increased the weight and bulkiness of the rifle, which made it more difficult to conceal and transport. And you clearly believe that an assassin could simply pickup that rifle and use the iron sights and rely on them to be adjusted accurately. Are you drunk?